drivers/gpu/drm/ttm/ttm_execbuf_util.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29 #include <drm/ttm/ttm_execbuf_util.h>
  30 #include <drm/ttm/ttm_bo_driver.h>
  31 #include <drm/ttm/ttm_placement.h>
  32 #include <linux/wait.h>
  33 #include <linux/sched.h>
  34 #include <linux/module.h>
  35
  36 static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
  37                                               struct ttm_validate_buffer *entry)
  38 {
  39         list_for_each_entry_continue_reverse(entry, list, head) {
  40                 struct ttm_buffer_object *bo = entry->bo;
  41
  42                 reservation_object_unlock(bo->resv);
  43         }
  44 }
  45
  46 static void ttm_eu_del_from_lru_locked(struct list_head *list)
  47 {
  48         struct ttm_validate_buffer *entry;
  49
  50         list_for_each_entry(entry, list, head) {
  51                 struct ttm_buffer_object *bo = entry->bo;
  52                 ttm_bo_del_from_lru(bo);
  53         }
  54 }
  55
  56 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
  57                                 struct list_head *list)
  58 {
  59         struct ttm_validate_buffer *entry;
  60         struct ttm_bo_global *glob;
  61
  62         if (list_empty(list))
  63                 return;
  64
  65         entry = list_first_entry(list, struct ttm_validate_buffer, head);
  66         glob = entry->bo->bdev->glob;
  67
  68         spin_lock(&glob->lru_lock);
  69         list_for_each_entry(entry, list, head) {
  70                 struct ttm_buffer_object *bo = entry->bo;
  71
  72                 if (list_empty(&bo->lru))
  73                         ttm_bo_add_to_lru(bo);
  74                 reservation_object_unlock(bo->resv);
  75         }
  76         spin_unlock(&glob->lru_lock);
  77
  78         if (ticket)
  79                 ww_acquire_fini(ticket);
  80 }
  81 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  82
  83 /*
  84  * Reserve buffers for validation.
  85  *
  86  * If a buffer in the list is marked for CPU access, we back off and
  87  * wait for that buffer to become free for GPU access.
  88  *
  89  * If a buffer is reserved for another validation, the validator with
  90  * the highest validation sequence backs off and waits for that buffer
  91  * to become unreserved. This prevents deadlocks when validating multiple
  92  * buffers in different orders.
  93  */
  94
  95 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  96                            struct list_head *list, bool intr,
  97                            struct list_head *dups, bool del_lru)
  98 {
  99         struct ttm_bo_global *glob;
 100         struct ttm_validate_buffer *entry;
 101         int ret;
 102
 103         if (list_empty(list))
 104                 return 0;
 105
 106         entry = list_first_entry(list, struct ttm_validate_buffer, head);
 107         glob = entry->bo->bdev->glob;
 108
 109         if (ticket)
 110                 ww_acquire_init(ticket, &reservation_ww_class);
 111
 112         list_for_each_entry(entry, list, head) {
 113                 struct ttm_buffer_object *bo = entry->bo;
 114
 115                 ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
 116                 if (!ret && unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 117                         reservation_object_unlock(bo->resv);
 118
 119                         ret = -EBUSY;
 120
 121                 } else if (ret == -EALREADY && dups) {
 122                         struct ttm_validate_buffer *safe = entry;
 123                         entry = list_prev_entry(entry, head);
 124                         list_del(&safe->head);
 125                         list_add(&safe->head, dups);
 126                         continue;
 127                 }
 128
 129                 if (!ret) {
 130                         if (!entry->num_shared)
 131                                 continue;
 132
 133                         ret = reservation_object_reserve_shared(bo->resv,
 134                                                                 entry->num_shared);
 135                         if (!ret)
 136                                 continue;
 137                 }
 138
 139                 /* uh oh, we lost out, drop every reservation and try
 140                  * to only reserve this buffer, then start over if
 141                  * this succeeds.
 142                  */
 143                 ttm_eu_backoff_reservation_reverse(list, entry);
 144
 145                 if (ret == -EDEADLK) {
 146                         if (intr) {
 147                                 ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
 148                                                                        ticket);
 149                         } else {
 150                                 ww_mutex_lock_slow(&bo->resv->lock, ticket);
 151                                 ret = 0;
 152                         }
 153                 }
 154
 155                 if (!ret && entry->num_shared)
 156                         ret = reservation_object_reserve_shared(bo->resv,
 157                                                                 entry->num_shared);
 158
 159                 if (unlikely(ret != 0)) {
 160                         if (ret == -EINTR)
 161                                 ret = -ERESTARTSYS;
 162                         if (ticket) {
 163                                 ww_acquire_done(ticket);
 164                                 ww_acquire_fini(ticket);
 165                         }
 166                         return ret;
 167                 }
 168
 169                 /* move this item to the front of the list,
 170                  * forces correct iteration of the loop without keeping track
 171                  */
 172                 list_del(&entry->head);
 173                 list_add(&entry->head, list);
 174         }
 175
 176         if (del_lru) {
 177                 spin_lock(&glob->lru_lock);
 178                 ttm_eu_del_from_lru_locked(list);
 179                 spin_unlock(&glob->lru_lock);
 180         }
 181         return 0;
 182 }
 183 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 184
 185 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 186                                  struct list_head *list,
 187                                  struct dma_fence *fence)
 188 {
 189         struct ttm_validate_buffer *entry;
 190         struct ttm_buffer_object *bo;
 191         struct ttm_bo_global *glob;
 192
 193         if (list_empty(list))
 194                 return;
 195
 196         bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
 197         glob = bo->bdev->glob;
 198
 199         spin_lock(&glob->lru_lock);
 200
 201         list_for_each_entry(entry, list, head) {
 202                 bo = entry->bo;
 203                 if (entry->num_shared)
 204                         reservation_object_add_shared_fence(bo->resv, fence);
 205                 else
 206                         reservation_object_add_excl_fence(bo->resv, fence);
 207                 if (list_empty(&bo->lru))
 208                         ttm_bo_add_to_lru(bo);
 209                 else
 210                         ttm_bo_move_to_lru_tail(bo, NULL);
 211                 reservation_object_unlock(bo->resv);
 212         }
 213         spin_unlock(&glob->lru_lock);
 214         if (ticket)
 215                 ww_acquire_fini(ticket);
 216 }
 217 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);